Polyether polyol and polyurethane compositions protected against oxidation and core scorching

ABSTRACT

Described are compositions protected against thermal and oxidative degradation that comprise 
     A) a polyether polyol or mixtures of such polyols, 
     B) at least one benzofuranone derivative of formula I, ##STR1##  wherein L, G, m, R 1  to R 5  and R 21  to R 24  are as defined in claim 1, 
     C) at least one compound from the group of the phenolic anti-oxidants, and/or 
     D) at least one compound from the group of the amino anti-oxidants of the secondary amine type. Also polyurethane(s) (foam(s)) prepared therefrom are protected against thermal and oxidative degradation, especially against core scorching.

This is a divisional of application Ser. No. 07/976,732, filed on Nov. 16, 1992, now U.S. Pat. No. 5,308,899, issued on May 3, 1994.

This invention relates to polyether polyol and polyurethane compositions that are protected especially against oxidation and against the undesired phenomenon of core scorching during the preparation of polyurethane foam by the presence of at least one benzofuran-2-one derivative and at least one further compound from the group of the phenolic anti-oxidants and/or from the group of the amino anti-oxidants of the secondary amine type, as well as to the use of the said derivatives and compounds as additives for the prevention of the said phenomena, and to a process for the preparation of polyurethane using those derivatives and compounds.

Currently, 2,6-di-tert-butyl-4-methylphenol ("butylated hydroxytoluene", "BHT") is generally used in practice for the above-mentioned purposes, but the improvements in stabilisation achieved with it are not satisfactory.

Combinations of specific anti-oxidants have also been proposed, such as mixtures of sterically hindered phenols (see, for example, U.S. Pat. No. 3,280,049, U.S. Pat. No. 4,007,230, U.S. Pat. No. 3,494,880), or mixtures of sterically hindered phenols with specific diphenylamines (see, for example, U.S. Pat. No. 4,070,304, U.S. Pat. No. 4,265,783, U.S. Pat. No. 4,275,173 and U.S. Pat. No. 4,021,385). The stabilisers and/or mixtures of stabilisers proposed in those specifications do not, however, meet the stringent demands made on them in practice.

Benzofuranone derivatives are already known as stabilisers for various organic materials (e.g. U.S. Pat. No. 4,611,016; EP-0 415 887).

Surprisingly, it has now been discovered that it is possible to prepare compositions that are very effectively protected against oxidation by adding to polyether polyols a combination of at least one benzofuran-2-one derivative with at least one further anti-oxidant from the group of the phenolic anti-oxidants and/or the amino anti-oxidants of the secondary amine type, from which compositions it is possible to produce polyurethane foams without the interference of core scorching.

The invention thus relates to compositions comprising

A) a polyether polyol or mixtures of such polyols,

B) at least one benzofuranone derivative of formula I ##STR2## wherein L is oxygen or, when G is a direct bond and R₁ hydrogen, C₁ -C₄ alkyl or C₁ -C₄ alkoxy, does not exist,

G is a direct bond or a group --CR₁₈ R₁₉ --CO--,

m is 1 or 2,

R₁, when m=1 and G is a direct bond, is hydrogen, C₁ -C₂₅ alkyl, C₃ -C₂₅ alkenyl, C₂ -C₁₈ alkanoyl, C₃ -C₂₅ alkenoyl, C₇ -C₉ phenylalkyl, unsubstituted or C₁ -C₄ alkyl-substituted phenyl, unsubstituted or C₁ -C₄ alkyl-substituted C₅ -C₈ cycloalkyl, C₃ -C₂₅ -alkyl, -alkanoyl or -alkenyl interrupted by oxygen, sulfur or by >NR₁₆, C₆ -C₉ cycloalkoxycarbonyl, benzoyl or C₁ -C₁₂ alkyl-substituted benzoyl,

or

R₁, when m=2 and G is a direct bond, is --CO--R₁₇ --CO--,

or

R₁, when m=1 and G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₃₀ alkoxy, C₃ -C₃₀ -alkoxy interrupted by oxygen, sulfur or by >NR₁₃, C₇ -C₉ phenylalkoxy, C₅ -C₁₂ -cycloalkoxy, C₂ -C₁₈ alkenyloxy, unsubstituted or C₁ -C₁₂ alkyl-substituted phenoxy, ##STR3## wherein p is 1 or 2, or ##STR4## or R₁, when m=2 and G is a group --CR₁₈ R₁₉ --CO--, is C₂ -C₁₂ alkanedioxy, C₃ -C₂₅ alkanedioxy interrupted by oxygen, sulfur or by >NR₁₆, ##STR5## --OCH₂ --CH═CH--CH₂ O-- or --OCH₂ --C≡C--CH₂ O--,

R₂ and R₄ are each, independently of the other, hydrogen or C₁ -C₆ alkyl,

R₃ and R₅ are each, independently of the other, hydrogen, C₁ -C₂₅ alkyl, C₇ -C₉ phenylalkyl, unsubstituted or C₁ -C₄ alkyl-substituted phenyl, unsubstituted or C₁ -C₄ alkyl-substituted C₅ -C₈ cycloalkyl, C₁ -C₁₈ alkoxy, hydroxy, C₁ -C₂₅ alkanoyloxy, C₃ -C₂₅ alkenoyloxy, C₃ -C₂₅ alkenyloxy interrupted by oxygen, sulfur or by >NR₁₆, C₆ -C₉ cycloalkylcarbonyloxy, benzoyloxy or C₁ -C₁₂ alkyl-substituted benzoyloxy, or a radical of the formula --(CH₂)_(n) --CO--OR₆, --(CH₂)_(n) --COR₁₁, or --(CH₂)_(n) --CO--N(R₇)₂,

R₃, when m=1, is furthermore a radical of the formula

    --(CH.sub.2).sub.n --CO--O--A*--O--CO--(CH.sub.2).sub.n --E, --(CH.sub.2).sub.n --CO--NR.sub.8 --A*--NR.sub.8 --CO--(CH.sub.2).sub.n --E, --(CH.sub.2).sub.n --CO--NR.sub.8 --A*--O--CO--(CH.sub.2).sub.n --E, ##STR6##

    --CH.sub.2 --S--R.sub.9, --CH(C.sub.6 H.sub.5)--CO--R.sub.6

or

when m=1 and R₄, R₅, R₂₁ and R₂₄ are hydrogen,

R₃ in addition is a radical of the formula ##STR7## R₂ together with R₃ or R₄ together with R₅, in each case together with the carbon atoms to which they are bonded, form a phenyl ring,

R₆ is hydrogen, C₂ -C₁₈ alkyl, C₁ -C₁₈ alkyl interrupted by oxygen or sulfur, C₃ -C₁₆ dialkylaminoalkyl, cyclohexyl, phenyl, or phenyl substituted by from 1 to 3 alkyl radicals together having a maximum of 18 carbon atoms,

n is 0, 1 or 2, the substituents

R₇ are each, independently of the other, hydrogen, C₁ -C₁₈ alkyl, cyclopentyl, cyclohexyl, phenyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, a radical of the formula --C₂ H₄ OH, --C₂ H₄ --O--C_(q) H_(2q+1) or --C₂ H₄ --O--CO--R₁₀, or, together with the nitrogen atom to which they are bonded, form a piperidine or morpholine radical, wherein q is 1 to 18,

R₈ is hydrogen, alkyl having from 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, benzyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms,

R₉ is alkyl having from 1 to 18 carbon atoms,

R₁₀ is hydrogen, alkyl having from 1 to 22 carbon atoms or cycloalkyl having from 5 to 12 carbon atoms,

R₁₁ is hydroxy, ##STR8## C₁ -C₁₈ alkoxy or --NR₁₄ R₁₅, R₁₂ and R₁₃ are each, independently of the other, hydrogen, C₁ -C₁₂ alkyl or phenyl, or form together with the C-atom to which they are bound a C₅ -C₇ -alkylidene-ring which is unsubstituted or substituted by 1 to 3 C₁ -C₄ alkyl groups,

R₁₄ and R₁₅ are each, independently of the other, hydrogen or C₁ -C₁₈ alkyl, M is an r-valent metal cation and r is 1, 2 or 3,

A* is an alkylene radical having from 2 to 22 carbon atoms that may or may not be interrupted by nitrogen, oxygen or by sulfur,

Y is --O--, --S--, --SO--, --SO₂ -- or --C(R₂₀)₂ --, wherein the substituents

R₂₀ are each, independently of the other, hydrogen, C₁ -C₁₆ alkyl, phenyl or a radical of the formula --(CH₂)_(n) --CO--OR₆ or --(CH₂)_(n) --CO--N(R₇)₂,

E is a radical of the formula ##STR9## R₁₆ is hydrogen or C₁ -C₈ alkyl, R₁₇ is a direct bond, C₁ -C₁₈ alkylene, C₂ -C₁₈ alkylene interrupted by oxygen, sulfur or by >NR₁₆, C₂ -C₁₈ alkenylene, C₂ -C₂₀ alkylidene, C₇ -C₂₀ phenylalkylidene, C₅ -C₈ cycloalkylene, C₇ -C₈ bicycloalkylene or phenylene,

R₁₈ and R₁₉ are each, independently of the other, hydrogen, C₁ -C₄ alkyl or phenyl, and

R₂₁, R₂₂, R₂₃ and R₂₄ are each, independently of the others, hydrogen, C₁ -C₄ alkyl or C₁ -C₄ alkoxy, provided that at least one of the radicals R₂₁, R₂₂, R₂₃ and R₂₄ is hydrogen,

C) at least one compound from the group of the phenolic anti-oxidants, and/or

D) at least one compound from the group of the amino anti-oxidants of the secondary amine type.

In a further embodiment the invention relates to compositions comprising

A) a polyether polyol or mixtures of such polyols,

B) at least one benzofuranone derivative of formula Ia ##STR10## wherein R ₁ is phenyl, or phenyl substituted by from 1 to 3 alkyl radicals together having a maximum of 12 carbon atoms or by alkoxy having from 1 to 12 carbon atoms,

R ₂ is hydrogen and R ₄ is hydrogen, alkyl having from 1 to 12 carbon atoms, cyclopentyl, cyclohexyl or chlorine,

R ₃ has the same meaning as R ₂ or R ₄ or is a radical of the formula --(CH₂)_(n) --CO--OR ₆, --(CH₂)_(n) --CO--N(R ₇)₂, --(CH₂)_(n) --CO--O--A*--O--CO--(CH₂)_(n) --E , --(CH₂)_(n) --CO--NR ₈ --A --NR ₈ --CO--(CH₂)_(n) --E , --(CH₂)_(n) --CO--NR ₈ --A --O--CO--(CH₂)_(n) --E , ##STR11## --CH₂ --S--R ₉, --CH(C₆ H₅)--CO--R ₆ or --Y --E wherein

R ₆ is hydrogen, alkyl having from 2 to 18 carbon atoms, alkyl having from 1 to 18 carbon atoms that is interrupted by oxygen or by sulfur, dialkylaminoalkyl having a total of from 3 to 16 carbon atoms, cyclopentyl, cyclohexyl, phenyl, or phenyl substituted by from 1 to 3 alkyl radicals together having a maximum of 18 carbon atoms,

n is 0, 1 or 2,

the substituents R ₇ are each, independently of the other, hydrogen, alkyl having from 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, a radical of the formula --C₂ H₄ OH, --C₂ H₄ --O--C_(q) H_(2q+1) or --C₂ H₄ --O--CO--R ₁₀, or, together with the nitrogen atom to which they are bonded, form a piperidine or morpholine radical,

q is from 1 to 18,

R ₁₀ is hydrogen, alkyl having from 1 to 22 carbon atoms or cycloalkyl having from 5 to 12 carbon atoms,

A is an alkylene radical having from 2 to 22 carbon atoms that may or may not be interrupted by nitrogen, oxygen or by sulfur,

R ₈ is hydrogen, alkyl having from 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, or benzyl,

R ₉ is alkyl having from 1 to 18 carbon atoms,

Y is --O--, --S--, --SO--, --SO₂ -- or --C(R ₁₁)₂ --,

the substituents R ₁₁ are each, independently of the other, hydrogen, alkyl wherein the the alkyl radicals together have a maximum of 16 carbon atoms, phenyl or a radical of the formula --(CH₂)_(n) --CO--OR ₆ or --(CH₂)_(n) --CO--N(R ₇)₂ wherein n, R ₆ and R ₇ have the meanings given,

E is a radical of the formula ##STR12## wherein R ₁, R ₂ and R ₄ have the meanings given, and R ₅ is hydrogen, alkyl having the 1 to 20 carbon atoms, cyclopentyl, cyclohexyl, chlorine or a radical of the formula --(CH₂)_(n) --CO--OR ₆ or --(CH₂)_(n) --CO--N(R ₇)₂ wherein R ₆ and R ₇ have the meanings given, or R ₅ together with R ₄ forms a tetramethylene radical,

C) at least one compound from the group of the phenolic anti-oxidants, and/or

D) at least one compound from the group of the amino anti-oxidants of the secondary amine type.

Preferably, the phenolic component C) corresponds to formula II, ##STR13## wherein A is hydrogen, C₁ -C₂₄ alkyl, C₅ -C₁₂ cycloalkyl, phenyl-C₁ -C₄ alkyl, phenyl or a group --CH₂ --S--R₂₅ or ##STR14## D is C₁ -C₂₄ alkyl, C₅ -C₁₂ cycloalkyl, phenyl-C₁ -C₄ alkyl, phenyl or a group --CH₂ --S--R₂₅,

X is hydrogen, C₁ -C₁₈ alkyl or one of the groups --C_(a) H_(2a) --S_(q) --R₂₆, --C_(b) H_(2b) --CO--OR₂₇, --C_(b) H_(2b) --CO--N(R₂₉)(R₃₀), --CH₂ N(R₃₄)(R₃₅), ##STR15## R is hydrogen or a group of the formula --CO--CH═CH₂, G* is hydrogen or C₁ -C₁₂ alkyl,

R₂₅ is C₁ -C₁₈ alkyl, phenyl or a group --(CH₂)_(c) --CO--OR₂₈ or --CH₂ CH₂ OR₃₃,

R₂₆ is hydrogen, C₁ -C₁₈ alkyl, phenyl, benzyl or a group ##STR16## or --(CH₂)_(c) --CO--OR₂₈ or --CH₂ --CH₂ --OR₃₃,

R₂₇ is C₁ -C₃₀ alkyl or one of the groups --CHR₃₁ --CH₂ --S--R₃₂, ##STR17## wherein Q is C₂ -C₈ alkylene, C₄ -C₆ thiaalkylene or a group --CH₂ CH₂ (OCH₂ CH₂)_(d) --,

R₂₈ is C₁ -C₂₄ alkyl,

R₂₉ is hydrogen, C₁ -C₁₈ alkyl or cyclohexyl,

R₃₀ is C₁ -C₁₈ alkyl, cyclohexyl, phenyl, phenyl substituted by C₁ -C₁₈ alkyl, or one of the groups ##STR18## R₂₉ and R₃₀ together are C₄ -C₈ alkylene that may be interrupted by --O-- or --NH--,

R₃₁ is hydrogen, C₁ -C₄ alkyl or phenyl,

R₃₂ is C₁ -C₁₈ alkyl,

R₃₃ is hydrogen, C₁ -C₂₄ alkyl, phenyl, C₂ -C₁₈ alkanoyl or benzoyl,

R₃₄ is C₁ -C₁₈ alkyl, cyclohexyl, phenyl, phenyl substituted by C₁ -C₁₈ alkyl, or a group ##STR19## R₃₅ is hydrogen, C₁ -C₁₈ alkyl, cyclohexyl, or a group ##STR20## R₃₄ and R₃₅ together are C₄ -C₈ alkylene, which may be interrupted by --O-- or --NH--,

R₃₆ and R₃₇ are --S--C₁ -C₁₈ alkyl,

a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, c is 1 or 2, d is from 1 to 5, f is from 2 to 8 and q is 1, 2, 3 or 4.

Component C) corresponds more preferably to compounds of formula II wherein

A is hydrogen, C₁ -C₈ alkyl, cyclohexyl, phenyl or a group --CH₂ --R₃₆ or ##STR21## D is C₁ -C₈ alkyl, cyclohexyl, phenyl or a group --CH₂ --R₃₇,

X is hydrogen, C₁ -C₈ alkyl or one of the groups --C_(a) H_(2a) --S_(q) --R₂₆, --C_(b) H_(2b) --CO--OR₂₇, --CH₂ N(R₃₄)(R₃₅), ##STR22## R₂₆ C₁ -C₁₂ alkyl, phenyl or a group --(CH₂)_(c) --CO--OR₂₈,

R₂₇ is C₁ -C₁₈ alkyl or a group ##STR23## wherein Q is C₂ -C₈ alkylene, --CH₂ --CH₂ --S--CH₂ CH₂ or a group --CH₂ CH₂ (OCH₂ CH₂)_(d) --,

R₂₈ is C₁ -C₁₈ alkyl,

R₃₄ and R₃₅ are each, independently of the other, hydrogen or C₁ -C₁₂ alkyl or

R₃₄ and R₃₅ together are C₄ -C₈ alkylene which may be interrupted by --O-- or --NH--,

a is 1 or 2, b is 1 or 2, c is 1 or 2, and d is 1, 2 or 3.

Most especially preferred as component C) are compounds of formula II wherein

A is hydrogen, C₁ -C₆ alkyl, --CH₂ --R₃₆ or a group ##STR24## D is hydrogen or C₁ -C₁₈ alkyl, and

X is hydrogen, C₁ -C₄ alkyl, --CH₂ --R₃₆ or a group of the formula ##STR25##

The amino component D) preferably corresponds to formula III ##STR26## wherein R₃₈ is C₁ -C₁₈ alkyl, phenyl-C₁ -C₄ alkyl, C₅ -C₁₂ cycloalkyl, phenyl, or phenyl or naphthyl substituted by C₁ -C₁₂ alkyl or by C₁ -C₁₂ alkoxy,

R₃₉ is phenyl, naphthyl, or phenyl or naphthyl substituted by C₁ -C₁₂ alkyl or by C₁ -C₁₂ alkoxy, or

R₃₈ and R₃₉ together form a radical of the formula IV ##STR27## wherein R₄₀ and R₄₁ are hydrogen or C₁ -C₁₈ alkyl or

R₄₁ is hydrogen or C₁ -C₁₈ alkyl and

R₄₀ together with R₄₂ forms a group of the formula ##STR28##

More preferably component D) corresponds to formula III wherein

R₃₈ and R₃₉ are each, independently of the other, phenyl or phenyl substituted by C₁ -C₁₂ -alkyl, or together form a radical of the formula IV.

In formula III R₃₈ and R₃₉ most preferably form a radical of the formula IV wherein R₄₀ and R₄₁ are C₆ -C₁₂ alkyl and R₄₂ is hydrogen, or component D) is a commercial mixture obtained by reacting diphenylamine with diisobutylene, comprising

a) diphenylamine;

b) 4-tert-butyldiphenylamine;

c) compounds from the group

i) 4-tert-octyldiphenylamine,

ii) 4,4'-di-tert-butyldiphenylamine,

iii) 2,4,4'-tris-tert-butyldiphenylamine,

d) compounds from the group

i) 4-tert-butyl-4'-tert-octyldiphenylamine,

ii) o,o'-, m,m'-, or p,p'-di-tert-octyldiphenylamine,

iii) 2,4-di-tert-butyl-4'-tert-octyldiphenylamine,

e) compounds from the group

i) 4,4'-di-tert-octyldiphenylamine,

ii) 2,4,-di-tert-octyl-4'-tert-butyldiphenylamine,

and wherein not more than 5% of component a), 8 to 15% b), 24 to 32% c), 23 to 34% d) and 21 to 34% e) are present.

Alkyl substituents in the compounds of formulae I, II and III may contain up to 30 carbon atoms. Examples of such substituents are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl or docosyl and corresponding branched isomers, especially tert-butyl, i-octyl and i-dodecyl. Alkoxy, alkanedioxy, alkanoyl and alkoxycarbonyl radicals are clearly derived from those groups as are also alkylene radicals contained in the definitions of the substituents shown in formulae I-III. The alkyl radicals listed and groups derived therefrom may be interrupted by oxygen or by sulfur in order especially to form structural units such as --CH₂ CH₂ --O--CH₂ CH₂ --, --CH₂ CH₂ --S--CH₂ CH₂ -- or --O--(CH₂)₆ --O--.

Alkenyl radicals are derived from alkyl radicals by the replacement of one or more C--C single bonds by C═C double bonds. Allyl and isoallyl are preferred. Alkenyloxy is derived from alkenyl by adding --O--.

If some radicals are C₅ -C₁₂ cycloalkyl, then those include, for example, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl and cyclododecyl. Cyclopentyl, cyclohexyl and cycloheptyl are preferred, with cyclohexyl being especially preferred. Cycloalkoxy and cycloalkoxycarbonyl radicals are derived therefrom by adding --CO-- or --O--CO-- groups.

Phenyl-C₁₋₄ alkyl and C₇ -C₉ phenylalkyl are, e.g., benzyl, phenethyl, 3-phenylpropyl, α-methylbenzyl and α,α-dimethylbenzyl. Benzyl is preferred.

The benzofuranones of formula I preferably used are those wherein

R₁, when m=1 and G is a direct bond, is hydrogen, C₁ -C₁₈ alkyl, C₃ -C₁₈ alkenyl, C₂ -C₁₈ alkanoyl, C₃ -C₁₈ alkenoyl, benzyl, phenyl or C₁ -C₄ alkyl-substituted phenyl, C₅ -C₈ cycloalkyl, C₃ -C₁₈ -alkyl, -alkanoyl or -alkenyl interrupted by oxygen, sulfur or by >NR₁₆, C₆ -C₉ cycloalkoxycarbonyl, benzoyl, or C₁ -C₈ alkyl-substituted benzoyl,

or

R₁, when m=2 and G is a direct bond, is --CO--R₁₇ --CO--,

or

R₁, when m=1 and G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₁₈ alkoxy, C₃ -C₁₈ -alkoxy interrupted by oxygen, sulfur or by >NR₁₃, benzyloxy, C₅ -C₈ cycloalkoxy, unsubstituted or C₁ -C₈ alkyl-substituted phenoxy, --NR₁₄ R₁₅ or ##STR29## or R₁, when m=2 and G is a group --CR₁₈ R₁₉ --CO--, is C₂ -C₁₂ alkanedioxy, or C₃ -C₂₅ -alkanedioxy interrupted by oxygen,

R₂ and R₄ are hydrogen,

R₃ and R₅ are each, independently of the other, hydrogen, C₁ -C₁₈ alkyl, C₇ -C₉ phenylalkyl, benzyl, phenyl, C₅ -C₈ cycloalkyl, C₁ -C₈ alkoxy, hydroxy, C₁ -C₁₈ alkanoyloxy, C₃ -C₁₈ alkenoyloxy or benzoyloxy, or a radical of the formula --(CH₂)_(n) --CO--OR₆ or --(CH₂)_(n) --CO--N(R₇)₂, and

R₃, when m=1, is in addition a radical of the formula --Y--E,

R₁₇ is a direct bond, C₁ -C₁₂ alkylene, C₂ -C₁₂ alkylene interrupted by oxygen, sulfur or by >NR₁₆, C₂ -C₁₂ alkenylene, C₂ -C₁₂ alkylidene, C₇ -C₁₂ phenylalkylidene, C₅ -C₈ cycloalkylene or phenylene.

Of those there are preferred compounds of formula I, wherein m=1 and

R₁, when G is a direct bond, is hydrogen, C₁ -C₁₈ alkyl, C₂ -C₁₈ alkanoyl, C₃ -C₄ alkenyl, C₃ -C₁₈ alkenoyl, benzyl, C₅ -C₈ cycloalkyl, or C₃ -C₁₈ -alkyl or -alkanoyl interrupted by oxygen,

or

R₁, when G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₁₈ alkoxy, C₃ -C₁₈ alkoxy interrupted by oxygen, unsubstituted or C₁ -C₈ alkyl-substituted phenoxy, --NR₁₄ R₁₅ or ##STR30## R₂, R₄, R₂₁ and R₂₄ are each, independently of the other, hydrogen or C₁ -C₄ alkyl,

R₅ is hydrogen or C₁ -C₁₄ alkyl, and

R₃ is hydrogen, C₁ -C₁₂ alkyl, C₁ -C₈ alkoxy, --(CH₂)_(n) --CO--OR₆, --(CH₂)_(n) --CO--N(R₇)₂, --(CH₂)_(n) --CO--OR₁₁ or --Y--E.

Among those preference is given to those compounds of formula I wherein

R₁, when G is a direct bond, is hydrogen, C₁ -C₁₈ alkyl, benzyl, allyl, isoallyl, C₁ -C₁₈ alkanoyl, or C₁ -C₁₂ alkanoyl interrupted by oxygen,

or

R₁, when G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₁₈ alkoxy, unsubstituted or C₁ -C₄ alkyl-substituted phenoxy, --NR₁₄ R₁₅ or ##STR31## R₂ and R₄ are hydrogen, R₃ and R₅ are each, independently of the other, C₁ -C₁₈ alkyl interrupted by oxygen, or C₁ -C₄ alkoxy or cyclohexyl and

R₃ in addition is a group --(CH₂)_(n) --CO--OR₁₁ wherein

R₁₁ is hydrogen or C₁ -C₄ alkyl, and

R₁₄ and R₁₅ are hydrogen or C₁ -C₄ alkyl.

The polyethers comprising at least two, generally from two to eight, preferably two or three, hydroxy groups that are suitable as component A) are of the type known per se and are prepared, for example, by polymerisation of epoxides, such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin, with themselves, for example in the presence of BF₃, or by addition of those epoxides, optionally as a mixture of one after another, to starting components having reactive hydrogen atoms, such as water, alcohols, ammonia or amines, for example ethylene glycol, propylene glycol-(1,3) and -(1,2), trimethylolpropane, 4,4'-dihydroxy-diphenylpropane, aniline, ethanolamine or ethylenediamine. Sucrose polyethers are also suitable according to the invention. In many cases, preference is given to polyethers having predominantly (up to 90% by weight, based on all the OH groups present in the polyether) primary OH groups. Also suitable are polyethers modified by vinyl polymers, such as those formed, for example, by polymerisation of styrene and acrylonitrile in the presence of polyethers, and polybutadienes comprising OH groups.

Those compounds generally have molecular weights of from 400-10,000. They are polyhydroxy compounds, especially compounds having from two to eight hydroxy groups, particularly those having a molecular weight of from 800 to 10,000, preferably from 1000 to 6000, for example polyethers having at least two, generally from 2 to 8, but preferably from 2 to 4, hydroxy groups, as known per se for the preparation of homogeneous and of cellular polyurethanes.

It is, of course, possible to use mixtures of the above-mentioned compounds comprising at least two hydrogen atoms that are reactive towards isocyanates, especially those having a molecular weight of from 400 to 10,000.

The compositions according to the invention are used especially in the preparation of polyurethane, especially in the preparation of soft polyurethane foams. The compositions according to the invention and the products prepared from them are effectively protected against degradation. In particular core scorching is avoided during foam preparation. In this connection the invention relates also to the use of the combination of component B) with component C) and/or component D) for the stabilisation of polyether polyols and/or soft polyurethane foams prepared therefrom, and also to a process for the preparation of polyurethanes which comprises reacting with a polyisocyanate a polyether polyol stabilised by the addition of component B) in combination with component C) and/or D), and to the polyurethane and the soft polyurethane foam obtained by that process.

Polyisocyanates that can be used in that process are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and any desired mixtures of those isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 2,4- and 2,6-hexahydrotolylene diisocyanate and any desired mixtures of those isomers, hexahydro-1,3- and/or -1,4-phenylene diisocyanate, perhydro-2,4'- and/or -4,4'-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate and any desired mixtures of those isomers, diphenylmethane-2,4'- and/or -4,4'-diisocyanate, naphthylene-1,5-diisocyanate, triphenylmethane-4,4',4"-triisocyanate, polyphenyl-polymethylene polyisocyanates, such as those obtained by means of aniline-formaldehyde condensation and subsequent phosgenation, m- and p-isocyanatophenylsulfonyl isocyanates, perchlorinated arylpolyisocyanates, polyisocyanates comprising carbodiimide groups, polyisocyanates comprising allophanate groups, polyisocyanates comprising isocyanurate groups, polyisocyanates comprising urethane groups, polyisocyanates comprising acylated urea groups, polyisocyanates comprising biuret groups, polyisocyanates comprising ester groups, reaction products of the above-mentioned isocyanates with acetals, and polyisocyanates comprising polymeric fatty acid radicals.

It is also possible to use the distillation residues comprising isocyanate groups that are obtained in the course of the industrial production of isocyanates, optionally dissolved in one or more of the above-mentioned polyisocyanates. If is also possible to use any desired mixtures of the above-mentioned polyisocyanates.

Special preference is generally given to polyisocyanates that are readily available commercially, for example 2,4- and 2,6-tolylene diosocyanate and any desired mixtures of those isomers ("TDI"), polyphenyl-polymethylene polyisocyanates, such as are prepared by aniline-formaldehyde condensation and subsequent phosgenation ("crude MDI"), and polyisocyanates comprising carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups ("modified polyisocyanates").

The benzofuran-2-ones of the formula Ia and processes for their preparation are described in U.S. Pat. No. 4,325,863 and U.S. Pat. No. 4,338,244.

The compounds of formula (I) can be prepared in a manner known per se.

For example, and this is preferred, a phenol of formula (V) ##STR32## is reacted with a mandelic acid substituted at the phenyl ring of formula (VI) or (VII) at elevated temperature, especially at temperatures of from 130° to 200° C. in the melt or in a solvent, optionally under a light vacuum. The reaction is preferably carried out in a solvent, such as, for example, acetic acid or formic acid, in a temperature range of from 50° to 130° C. The reaction can be catalysed by adding an acid, such as hydrochloric acid, sulfuric acid or methanesulfonic acid. The reaction can be carried out, for example, as described in the literature sources indicated in the introduction of the description.

The 4-hydroxymandelic acids substituted at the phenyl ring of formula (VI) are known in the literature, or can be prepared analogously to the method, for example, according to W. Bradley et al, J. Chem. Soc. 1956, 1622; EP-A-146269 or DE 2 944 295.

The 4-carboxymethoxymandelic acids substituted at the phenyl ring of formula (VII), wherein R₁ is hydroxy, can be etherified according to generally known etherification conditions starting from phenols of formula (VI), e.g. according to Organikum 1986, pages 194-200, for example by alkylation under basic conditions with an α-chloroacetic acid derivative of formula ##STR33##

The phenols of formula (V) are also known or can be obtained according to processes known per se. ##STR34##

Bisphenol compounds of formula VIII can be prepared according to Houben-Weyl, Methoden der organischen Chemie, Volume 6/1c, 1030.

The 3-(carboxymethoxyphenyl)benzofuran-2-ones of formula I wherein R₁ is hydroxy, m is 1 and G is a group --CR₁₈ R₁₉ --CO-- obtained by that reaction can be derivatised according to generally known esterification and amidation methods, e.g. according to Organikum 1986, pages 402-410 with m-valent alcohols or with primary or secondary amines of formula ##STR35##

The phenols of formula (I) wherein R₁ is hydrogen, G is a direct bond and m=1 obtained by that reaction can be etherified according to generally known etherification methods, e.g. according to Organikum 1986, pages 194-200, for example by alkylation under basic conditions with an alkyl halide of formula R₁ ¹ Br, a dialkyl sulfate of formula (R₁ ¹)₂ SO₄ or an alkyl tosylate of formula ##STR36## wherein R₁ ¹ has the same meaning as R₁ with the exception of hydrogen.

The phenols of formula (I) obtained by that reaction wherein R₁ is hydrogen and G is a direct bond can be esterified according to generally known esterifications methods, e.g. according to Organikum 1986, pages 402-408, for example by acylation with an acid chloride or acid anhydride of formula R₁ ¹ Cl or R₁ ¹ --O--R₁ ¹ respectively wherein R₁ ¹ has the same meaning as R₁ with the exception of hydrogen.

The phenolic and amino anti-oxidants are either commercially available or can be prepared according to processes known per se.

In the polyol compositions according to the invention, the components B), C) and D) together are advantageously present in an amount of from 0.01 to 10, for example from 0.05 to 5, preferably from 0.05 to 3, but especially from 0.1 to 2% by weight. The ratios by weight of B:C, B:D and B:C:D can vary within wide limits and are advantageously from 10:1 to 1:10 or within the limits 10:1:1, 1:1:10 and 1:10:1, e.g. 5:1:1 (1:5:1, 1:1:5) or 2:1:1 (1:2:1, 1:1:2) respectively. It may also be advantageous to use the three components in approximately equimolar amounts.

The polyol compositions according to the invention are preferably used for the preparation of polyurethanes, especially polyurethane foams, with propellants advantageously being used.

In the preparation of polyurethanes it is therefore possible in addition to add as propellant water and/or readily volatile organic substances. Suitable organic propellants are, e.g., acetone, ethyl acetate, halo-substituted alkanes, such as methylene chloride, chloroform, ethylidene chloride, vinylidene chloride, monofluorotrichloromethane, chlorodifluoromethane, dichlorodifluoromethane, and also butane, hexane, heptane or diethyl ether. A propellant action can also be achieved by adding compounds that decompose at temperatures above room temperature to split off gases, for example nitrogen, e.g. azo compounds such as azoisobutyronitrile.

The process according to the invention for the preparation of polyurethanes is advantageously carried out in the presence of suitable catalysts. The catalysts used are catalysts that are known per se, such as e.g. tertiary amines, such as triethylamine, tributylamine, N-methyl-morpholine, N-ethyl-morpholine, N-cocomorpholine, N,N,N',N'-tetramethylethylenediamine, 1,4-diazabicyclo-(2,2,2)-octane, N-methyl-N'-dimethylaminoethylpiperazine, N,N-dimethylbenzylamine, bis(N,N-diethylaminoethyl) adipate, N,N-diethylbenzylamine, pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethyl-1,3-butanediamine, N,N-dimethyl-β-phenylethylamine, 1,2-dimethylimidazole and 2-methylimidazole, also Mannich bases known per se formed from secondary amines, such as dimethylamine, and aldehydes, preferably formaldehyde, or ketones, such as acetone, methyl ethyl ketone or cyclohexanone, and phenols, such as phenol, nonylphenol or bisphenol.

Examples of tertiary amines comprising hydrogen atoms active towards isocyanate groups that may be used as catalysts are triethanolamine, triisopropanolamine, N-methyl-diethanolamine, N-ethyl-diethanolamine, N,N-dimethyl-ethanolamine, and reaction products thereof with alkylene oxides, such as propylene oxide and/or ethylene oxide.

Further suitable catalysts are silaamines having carbon-silicon bonds, such as 2,2,4-trimethyl-2-silamorpholine and 1,3-diethylaminomethyl-tetramethyl-disiloxane, and nitrogen-containing bases, such as tetraalkylammonium hydroxides, and alkali metal hydroxides, such as sodium hydroxide, alkali metal phenolates, such as sodium phenolate, or alkali metal alcoholates, such as sodium methoxide, or hexahydrotriazines, and organometallic compounds, especially organotin compounds, for example tin(II) salts of carboxylic acid, such as tin(II) acetate, tin(II) octoate, tin(II) ethylhexoate and tin(II) laurate, and the tin(IV) compounds, for example dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate or dioctyltin diacetate. It is, of course, possible for all of the above-mentioned catalysts to be used in the form of mixtures.

Other additives known per se, for example surface-active additives, such as emulsifiers and foam stabilisers, are optionally also present.

Examples of suitable emulsifiers are the sodium salts of ricinoleic sulfonates or salts of fatty acids with amines, such as diethylamine oleate or diethanolamine stearate. Alkali metal or ammonium salts of sulfonic acids, for example of dodecylbenzenesulfonic acid or dinaphthylmethanedisulfonic acid, or of fatty acids, such as ricinoleic acid, or of polymeric fatty acids, may also be used as surface-active additives.

Suitable foam stabilisers are especially polyether siloxanes, especially water-soluble representatives thereof. The structure of those compounds is generally such that a copolymer of ethylene oxide and propylene oxide is bonded to a polydimethylsiloxane radical.

Further additives that may also be present in the compositions are reaction retardants, for example substances with an acid reaction, such as hydrochloric acid or organic acid halides, also cell regulators of the type known per se, such as paraffins or fatty alcohols, or dimethylpolysiloxanes and pigments or dyes and flame-retardants of the type known per se, for example trischloroethyl phosphate, tricresyl phosphate or ammonium phosphate and polyphosphate, and stabilisers that counteract the effects of ageing and weathering, plasticisers and fungistats and bacteriostats, as well as fillers, such as barium sulfate, diatomaceous earth, carbon black or prepared chalk.

Further examples of surface-active additives and foam stabilisers as well as cell regulators, reaction retardants, stabilisers, flame-retardants, plasticisers, dyes and fillers and also fungistats and bacteriostats that are optionally present and details of the method of use and mode of action of those additives are well known to a person skilled in the art.

Using the process according to the invention, it is possible to prepare polyurethane substances in any desired form, such as articles of any desired form and also fibres. Preference is given, however, to the preparation of foams, it being possible, by suitable selection of the components, to obtain either flexible or rigid foams or any products between those extremes.

Polyurethane foams are preferably prepared from liquid starting components, with either the starting materials to be reacted with one another being mixed together in a one-shot process, or a preadduct containing NCO groups that is formed from a polyol and an excess of polyisocyanate being prepared first and then foamed, for example by reaction with water.

According to the invention, the reaction components are reacted in accordance with the one-shot process known per se, the prepolymer process or the semi-prepolymer process, mechanical devices that are well known to a person skilled in the art often being used.

In the preparation of foams, the foaming is often carried out in moulds. In that case, the reaction mixture is introduced into a mould. Suitable mould materials are metals, for example aluminium, or plastics, for example epoxy resin. In the mould the foamable reaction mixture foams up and forms the moulded article. The formation of foam using a mould can be carried out in such a manner that the moulding has a cellular surface structure, or, alternatively, it can be carried out in such a manner that the moulding has a dense skin and a cellular core. In this connection, it is possible to introduce into the mould an amount of foamable reaction mixture sufficient for the foam that forms to fill the mould exactly. It is, however, also possible to introduce more foamable reaction mixture into the mould than is required to fill the interior of the mould with foam. In the last-mentioned case, therefore, the operation is carried out with "overcharging".

In the case of foam formation in a mould "external release agents" known per se, such as silicone oils, are often used concomitantly. It is, however, also possible to use so-called "internal release agents", optionally in admixture with external release agents.

It is also possible according to the invention to use cold-hardening foams. The foams can, of course, alternatively be prepared by means of block foaming or by means of the double conveyor belt process which is known per se.

The process according to the invention can be used to prepare flexible, semi-flexible or hard polyurethane foams. The foams have the uses known per se for such products, for example as mattresses and upholstery in the furniture and automobile industries, and also for the manufacture of fittings, such as are used in the automobile industry, and finally as sound-insulating compositions and as compositions for heat-insulation and low-temperature insulation, for example in the construction sector or in the refrigeration industry, or in the textile industry, for example as shoulder pads.

The following Examples further illustrate the invention but without implying any limitation. Unless indicated otherwise, parts and percentages relate, as in the remainder of the description, to weight.

The components contained in the stabiliser mixtures used are listed in the following together with their abbreviations:

Benzofuranone components: ##STR37## Amino anti-oxidants:

A1: Commercial mixture, obtained by reaction of diphenylamine with diisobutylene, comprising

a) 3% diphenylamine;

b) 14% 4-tert-butyldiphenylamine;

c) 30% compounds from the group

i) 4-tert-octyldiphenylamine,

ii) 4,4'-di-tert-butyldiphenylamine,

iii) 2,4,4'-tris-tert-butyldiphenylamine,

d) 29% compounds from the group

i) 4-tert-butyl-4'-tert-octyldiphenylamine,

ii) o,o'-, m,m'-, or p,p'-di-tert-octyldiphenylamine,

iii) 2,4-di-tert-butyl-4'-tert-octyldiphenylamine,

e) 24% compounds from the group

i) 4,4'-di-tert-octyldiphenylamine (18%),

ii) 2,4-di-tert-octyl-4'-tert-butyldiphenylamine (6%), ##STR38## Phenolic anti-oxidants: ##STR39##

EXAMPLES 1-14 Soft Polyether/Polyurethane Foams and the Stabilisation Thereof

Exactly 470 mg (0.3%, based on the polyol) of a stabiliser mixture according to the invention (see numbered Examples, Tables 1, 2 and 4) are dissolved in 157 g of an anti-oxidant-free polyether polyol, ®Lupranol 2045 (trifunctional polyether polyol having primary hydroxy groups; hydroxy number 35 mg KOH/g, water content less than 0.1%, acid number less than 0.1 mg KOH/g).

                  TABLE 4                                                          ______________________________________                                                                   Conc. in % based                                     Ex. No.    Stabiliser mixture                                                                            on polyol                                            ______________________________________                                          0         --             --                                                   21         B3/P2/A1       0.1/0.1/0.1                                          22         B4/P2/A1       0.1/0.1/0.1                                          23         B5/P2/A1       0.1/0.1/0.1                                          ______________________________________                                    

10.24 g of a solution of 1.74 g of ®TECOSTAB [polysilicone produced by Goldschmidt, DE], 0.48 g of diazabicyclooctane [amine catalysts] and 0.8 g of water are added thereto and the reaction mixture is stirred intensively at 100 rpm for 60 seconds.

3.2 of a solution of 0.32 g of tin octoate (catalyst) in 2.9 g of the above polyol are then added thereto and the reaction mixture is again stirred intensively for 60 sec. at 100 rpm. Immediately, while stirring intensively, 98 g of an isocyanate (®Lupranat T80 produced by BASF; tolylene-2,4- and -2,6-diisocyanate mixture) are added thereto and after 6 sec. the reaction mixture is poured into a lined mould and the exothermic temperature is measured during foaming to form a foam block.

The foam blocks are cooled for 24 hours in a climatic chamber at 5° C. and stored. Slices 2 cm thick are sawed from the middle of the blocks and round (cylindrical) test samples are cut therefrom using a boring tool. The samples are aged in a test tube in the presence of air at 190° C. in a preheated alu-block thermostat.

The yellowing of those samples is determined as the Yellowness Index (YI) in accordance with ASTM D-1925.

The resistance of the stabilised polyurethane foam to oxidation is determined by measuring the DSC value (differential scanning calorimetry, temperature-controlled calorimetry). For that purpose, 20 mg of the sample are weight into an aluminium crucible and heated from a starting temperature of 50° C. at a rate of 5° C./min. The beginning of the exothermic oxidation is determined calorimetrically by means of a temperature-controlled measurement against an unstabilised reference substance. The temperature at which oxidation begins, and the temperature difference (ΔT) between the temperature measured for the respective stabilised samples and the corresponding temperature of the unstabilised polyol are given. High values denote a high degree of resistance to oxidation.

The results are summarised in Tables 1 and 2 below.

                                      TABLE 1                                      __________________________________________________________________________               Concen-                                                                        tration                       Oxidation                                        in %,                         resistance                                       based                         acc. to                                Ex.                                                                               Stabiliser                                                                            on    YI after oven ageing:   DSC method                             No.                                                                               mixture                                                                               polyol                                                                               0  10                                                                               20                                                                               30                                                                               40                                                                               60                                                                               80                                                                               100                                                                               120 (Min.)                                                                           T (°C.)                                                                     ΔT                           __________________________________________________________________________     0  --     --    -0.7                                                                              44                                                                               48                                                                               55                                                                               57                                                                               62           171  0                                 1  B1/P2  0.2/0.1                                                                              1.1                                                                               2.7                                                                              2.9                                                                              4.8                                                                              7.2                                                                              42                                                                               53         198 27                                 2  B1/P5  0.210.1                                                                              0.3                                                                               2.1                                                                              2.6                                                                              3.7                                                                              4.6                                                                              7.9                                                                              16                                                                               23 33    205 34                                 3  B1/P1  0.2/0.1                                                                              1.1                                                                               2.3                                                                              2.9                                                                              3.3                                                                              4.1                                                                              5.6                                                                              6.7                                                                              19 28    208 37                                 4  B1/A1  0.2/0.1                                                                              1.1                                                                               2.2                                                                              2.4                                                                              3.5                                                                              4.2                                                                              6.5                                                                              12                                                                               19 26    210 35                                 5  B1/P3  0.2/0.1                                                                              0  1.5                                                                              1.8                                                                              2.9                                                                              3.3                                                                              22                                                                               26                                                                               33 41    200 29                                 6  B1/P2/P1                                                                              0.1/0.1/0.1                                                                          -0.5                                                                              0.8                                                                              1.2                                                                              1.9                                                                              2.1                                                                              3.8                                                                              4.2                                                                              9.4                                                                               13    205 34                                 7  B1/P2/P5                                                                              0.1/0.1/0.1                                                                          -0.6                                                                              1.0                                                                              1.4                                                                              2.3                                                                              3.1                                                                              5.5                                                                              10                                                                               24 31    208 37                                 8  B1/P2/A1                                                                              0.1/0.1/0.1                                                                          -0.2                                                                              0.8                                                                              1.3                                                                              2.2                                                                              2.8                                                                              3.6                                                                              5.3                                                                              9.2                                                                               13    211 40                                 9  B1/P2/P1/A1                                                                           0.05 each                                                                            -0.5                                                                              0.7                                                                              1.2                                                                              1.7                                                                              2.4                                                                              4.2                                                                              5.7                                                                              11 21    206 35                                 __________________________________________________________________________

                                      TABLE 2                                      __________________________________________________________________________             Concen-                                                                        tration                       Oxidation                                        in %,                         resistance                                       based                         acc. to                                  Ex.                                                                               Stabiliser                                                                          on   YI after oven ageing:    DSC method                               No.                                                                               mixture                                                                             polyol                                                                              0  20                                                                               30                                                                               40                                                                               60                                                                               80                                                                               100                                                                               120                                                                               140                                                                               160                                                                               T (°C.)                                                                     ΔT                             __________________________________________________________________________      0 --   --   -0.7                                                                              48                                                                               55                                                                               57                                                                               62              175  0                                   10 B2/A2                                                                               0.25/0.05                                                                           1.9                                                                               2.4                                                                              4.1                                                                              6.5                                                                              11                                                                               16                                                                               22 24 31 33 220 45                                   11 B2/P2                                                                               0.25/0.05                                                                           -1.6                                                                              2.1                                                                              4.4                                                                              5.9                                                                              11                                                                               23                                                                               34 39 46 53 194 19                                   12 B2/P1                                                                               0.25/0.05                                                                           -1.8                                                                              1.7                                                                              2.6                                                                              3.7                                                                              5.1                                                                              10                                                                               20 24 36 39 208 33                                   13 B2/A1                                                                               0.25/0.05                                                                           -1.7                                                                              1.8                                                                              3.1                                                                              5.9                                                                              7.3                                                                              12                                                                               21 27 35 38 208 33                                   14 B2/P5                                                                               0.25/0.05                                                                           -1.7                                                                              1.9                                                                              3.5                                                                              4.7                                                                              7.5                                                                              13                                                                               23 31 39 43 202 27                                   __________________________________________________________________________

The action of the stabiliser combinations according to the invention is excellent. The yellowing remains low for a long time (low Yellowness Index values denote a low degree of yellowing).

EXAMPLES 15-20

With the DSC method described above, the resistance to oxidation of the polyether polyols themselves is also measured. The oxidation time indicated in each case is the time that has passed until the exothermic reaction commences, that is to say long times denote good stabilisation.

The results are illustrated in the following Table 3.

                  TABLE 3                                                          ______________________________________                                         Example  Compo-     Concentration                                                                              Oxidation                                      No.      nent       [ppm]       time [min]                                     ______________________________________                                         00       --         --           0                                             15       B1         2000        315                                                     P1         1000                                                       16       B1         1000        346                                                     P1         1000                                                                P2         1000                                                       17       B1         2000        272                                                     P5         1000                                                       18       B1         2000        179                                                     A1         1000                                                       19       B1         1000        236                                                     A1         1000                                                                P2         1000                                                       20       B1          500        300                                                     P2          500                                                                P1          500                                                                A1          500                                                       ______________________________________                                    

The compositions according to the invention are shown to have a high degree of stability. 

What is claimed is:
 1. A process for preparing a polyurethane which comprises reacting a stabilized composition which comprisesA) a polyether polyol or mixtures of such polyols, B) at least one benzofuranone derivative of formula I ##STR40## wherein L is oxygen or, when G is a direct bond and R₁ is hydrogen, C₁ -C₄ alkyl or C₁ -C₄ alkoxy, L is a direct bond,G is a direct bond or a group --CR₁₈ R₁₉ --CO--, m is 1 or 2, R₁, when m=1 and G is a direct bond, is hydrogen, C₁ -C₂₅ alkyl, C₃ -C₂₅ alkenyl, C₂ -C₁₈ alkanoyl, C₃ -C₂₅ alkenoyl, C₇ -C₉ phenylalkyl, unsubstituted or C₁ -C₄ alkyl-substituted phenyl, unsubstituted or C₁ -C₄ alkyl-substituted C₅ -C₈ cycloalkyl, C₃ -C₂₅ -alkyl, -alkanoyl or -alkenyl interrupted by oxygen, sulfur or by >NR₁₆, C₆ -C₉ cycloalkoxycarbonyl, benzoyl or C₁ -C₁₂ alkyl-substituted benzoyl, or R₁, when m=2 and G is a direct bond, is --CO--R₁₇ --CO--, or R₁, when m=1 and G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₃₀ alkoxy, C₃ -C₃₀ alkoxy interrupted by oxygen, sulfur or by >NR₁₃, C₇ -C₉ -phenylalkoxy, C₅ -C₁₂ cycloalkoxy, C₂ -C₁₈ alkenyloxy, unsubstituted or C₁ -C₁₂ alkyl-substituted phenoxy, ##STR41## wherein p is 1 or 2, or ##STR42## or R₁, when m=2 and G is a group --CR₁₈ R₁₉ --CO--, is C₂ -C₁₂ alkanedioxy, C₃ -C₂₅ alkanedioxy interrupted by oxygen, sulfur or by >NR₁₆, ##STR43## --OCH₂ --CH═CH--CH₂ O-- or --OCH₂ --C≡C--CH₂ O--, R₂ and R₄ are each, independently of the other, hydrogen or C₁ -C₆ alkyl, R₃ and R₅ are each, independently of the other, hydrogen, C₁ -C₂₅ alkyl, C₇ -C₉ phenylalkyl, unsubstituted or C₁ -C₄ alkyl-substituted phenyl, unsubstituted or C₁ -C₄ alkyl-substituted C₅ -C₈ cycloalkyl, C₁ -C₁₈ alkoxy, hydroxy, C₁ -C₂₅ alkanoyloxy, C₃ -C₂₅ alkenoyloxy, C₃ -C₂₅ alkenyloxy interrupted by oxygen, sulfur or by >NR₁₆, C₆ -C₉ cycloalkylcarbonyloxy, benzoyloxy or C₁ -C₁₂ alkyl-substituted benzoyloxy, or a radical of the formula --(CH₂)_(n) --CO--OR₆, --(CH₂)_(n) --COR₁₁ or --(CH₂)_(n) --CO--N(R₇)₂, R₃, when m=1, is furthermore a radical of the formula

    --(CH.sub.2).sub.n --CO--O--A*--O--CO--(CH.sub.2).sub.n --E, --(CH.sub.2).sub.n --CO--NR.sub.8 --A*--NR.sub.8 --CO--(CH.sub.2).sub.n --E, --CH.sub.2).sub.n --CO--NR.sub.8 --A*--O--CO--(CH.sub.2).sub.n --E, ##STR44##

    --CH.sub.2 --S--R.sub.9, --CH(C.sub.6 H.sub.5)--CO--R.sub.6 or

when m=1 and R₄, R₅, R₂₁ R₂₄ are hydrogen, R₃ in addition is a radical of the formula ##STR45## R₂ together with R₃ or R₄ together with R₅, in each case together with the carbon atoms to which they are bonded, form a phenyl ring, R₆ is hydrogen, C₂ -C₁₈ alkyl, C₁ -C₁₈ alkyl interrupted by oxygen or by sulfur, C₃ -C₁₆ dialkylaminoalkyl, cyclohexyl, phenyl, or phenyl substituted by from 1 to 3 alkyl radicals together having a maximum of 18 carbon atoms, n is 0, 1 or 2, the substituents R₇ are each, independently of the other, hydrogen, C₁ -C₁₈ alkyl, cyclopentyl, cyclohexyl, phenyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, a radical of the formula --C₂ H₄ OH, --C₂ H₄ --O--C_(q) H_(2q+1) or --C₂ H₄ --O--CO--R_(10'), together with the nitrogen atom to which they are bonded, form a piperidine or morpholine radical, wherein q is 1 to 18, R₈ is hydrogen, alkyl having from 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, benzyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, or benzyl, R₉ is alkyl having from 1 to 18 carbon atoms, R₁₀ is hydrogen, alkyl having from 1 to 22 carbon atoms or cycloalkyl having from 5 to 12 carbon atoms R₁₁ is hydroxy, ##STR46## C₁ -C₁₈ alkoxy or --NR₁₄ R₁₅, R₁₂ and R₁₃ are each, independently of the other, hydrogen, C₁ -C₁₂ alkyl or phenyl, or form together with the C-atom to which they are bound a C₅ -C₇ -alkylidene-ring which is unsubstituted or substituted by 1 to 3 C₁ -C₄ alkyl groups, R₁₄ and R₁₅ are each, independently of the other, hydrogen or C₁ -C₁₈ alkyl, M is an r-valent metal cation and r is 1, 2 or 3, A* is an alkylene radical having from 2 to 22 carbon atoms that may or may not be interrupted by nitrogen, oxygen or by sulfur, Y is --O--, --S--, --SO--, --SO₂ -- or --C(R₂₀)₂ --, wherein the substituents R₂₀ are each, independently of the other, hydrogen, C₁ -C₁₆ alkyl, phenyl or a radical of the formula --(CH₂)_(n) --CO--OR₆ or --(CH₂)_(n) --CO--N(R₇)₂, E is a radical of the formula ##STR47## R₁₆ is hydrogen or C₁ -C₈ alkyl, R₁₇ is a direct bond, C₁ -C₁₈ alkylene, C₂ -C₁₈ alkylene interrupted by oxygen, sulfur or by >NR₁₆, C₂ -C₁₈ alkenylene, C₂ -C₂₀ alkylidene, C₇ -C₂₀ phenylalkylidene, C₅ -C₈ cycloalkylene, C₇ -C₈ bicycloalkylene or phenylene, R₁₈ and R₁₉ are each, independently of the other, hydrogen, C₁ -C₄ alkyl or phenyl, and R₂₁, R₂₂, R₂₃ R₂₄ are each, independently of the others, hydrogen, C₁ -C₄ alkyl or C₁ -C₄ alkoxy, provided that at least one of the radicals R₂₁, R₂₂, R₂₃ and R₂₄ is hydrogen, C) at least one compound from the group of the phenolic anti-oxidants, and D) at least one compound of formula III ##STR48## wherein R₃₈ is C₁ -C₁₈ alkyl, phenyl-C₁ -C₄ alkyl, C₅ -C₁₂ cycloalkyl, phenyl, naphthyl, or phenyl or naphthyl substituted by C₁ -C₁₂ alkyl or by C₁ -C₁₂ alkoxy,R₃₉ is phenyl, naphthyl, or phenyl or naphthyl substituted by C₁ -C₁₂ alkyl or by C₁ -C₁₂ alkoxy, or R₃₈ and R₃₉ together form a radical of the formula IV ##STR49## wherein R₄₀ and R₄₁ are hydrogen or C₁ -C₁₈ alkyl or R₄₁ is hydrogen or C₁ -C₁₈ alkyl and R₄₀ together with R₄₂ forms a group of the formula ##STR50## or, a composition comprising (A), (B) and (D), with a polyisocyanate.
 2. A process according to claim 1 wherein the reaction is carried out in the presence of a catalyst.
 3. A process according to claim 1 wherein the reaction is carried out in the presence of a propellant to form a polyurethane foam.
 4. A process according to claim 1 where in the stabilized composition, component B) is at least one benzofuranone derivative of formula Ia ##STR51## wherein R ₁ is phenyl, or phenyl substituted by from 1 to 3 alkyl radicals together having a maximum of 12 carbon atoms or by alkoxy having from 1 to 12 carbon atoms,R ₂ is hydrogen and R ₄ is hydrogen, alkyl having from 1 to 12 carbon atoms, cyclopentyl, cyclohexyl or chlorine, R ₃ has the same meaning as R ₂ or R ₄ or is a radical of the formula --(CH₂)_(n) --CO--OR ₆, --(CH₂)_(n) --CO--N(R ₇)₂, --(CH₂)_(n) --CO--O--A --O--CO--(CH₂)_(n) --E , --(CH₂)_(n) --CO--NR ₈ --A --NR ₈ --CO--(CH₂)_(n) --E , --(CH₂)_(n) --CO--NR ₈ --A --O--CO--(CH₂)_(n) --E , ##STR52## --CH₂ --S--R ₉, --CH(C₆ H₅)--CO--R ₆ or --Y --E wherein R ₆ is hydrogen, alkyl having from 2 to 18 carbon atoms, alkyl having from 1 to 18 carbon atoms that is interrupted by oxygen or by sulfur, dialkylaminoalkyl having a total of from 3 to 16 carbon atoms, cyclopentyl, cyclohexyl, phenyl, or phenyl substituted by from 1 to 3 alkyl radicals together having a maximum of 18 carbon atoms, n is 0, 1 or 2, the substituents R ₇ are each, independently of the other, hydrogen, alkyl having from 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, a radical of the formula --C₂ H₄ OH, --C₂ H₄ --O--C_(q) H_(2q+1) or --C₂ H₄ --O--CO--R ₁₀, or, together with the nitrogen atom to which they are bonded, form a piperidine or morpholine radical, q is from 1 to 18, R ₁₀ is hydrogen, alkyl having from 1 to 22 carbon atoms or cycloalkyl having from 5 to 12 carbon atoms, A is an alkylene radical having from 2 to 22 carbon atoms that may or may not be interrupted by nitrogen, oxygen or by sulfur, R ₈ is hydrogen, alkyl having from 1 to 18 carbon atoms, cyclopentyl, cyclohexyl, phenyl, phenyl substituted by 1 or 2 alkyl radicals together having a maximum of 16 carbon atoms, or benzyl, R ₉ is alkyl having from 1 to 18 carbon atoms, Y is --O--, --S--, --SO--, --SO₂ -- or --C(R ₁₁)₂ --, the substituents R ₁₁, are each, independently of the other, hydrogen, alkyl wherein the alkyl radicals together have a maximum of 16 carbon atoms, phenyl or a radical of the formula --(CH₂)_(n) --CO--OR ₆ or --(CH₂)_(n) --CO--N(R ₇)₂ wherein n, R ₆ and R ₇ have the meanings given, E is a radical of the formula ##STR53## wherein R ₁, R ₂ and R ₄ have the meanings given, and R ₅ is hydrogen, alkyl having from 1 to 20 carbon atoms, cyclopentyl, cyclohexyl, chlorine or a radical of the formula --(CH₂)_(n) --CO--OR ₆ or --(CH₂)_(n) --CO--N(R ₇)₂ wherein R ₆ and R ₇ have the meanings given, or R ₅ together with R ₄ forms a tetramethylene radical.
 5. A process according to claim 1 where in the stabilized composition, component C) corresponds to formula II ##STR54## wherein A is hydrogen, C₁ -C₂₄ alkyl, C₅ -C₁₂ cycloalkyl, phenyl-C₁ -C₄ alkyl, phenyl or a group --CH₂ --S--R₂₅ or ##STR55## D is C₁ -C₂₄ alkyl, C₅ -C₁₂ cycloalkyl, phenyl-C₁ -C₄ alkyl, phenyl or a group --CH₂ --S--R₂₅,X is hydrogen, C₁ -C₁₈ alkyl or one of the groups --C_(a) H_(2a) --S_(q) --R₂₆, --C_(b) H_(2b) --CO--OR₂₇, --C_(b) H_(2b) --CO--N(R₂₉)(R₃₀), --CH₂ N(R₃₄)(R₃₅), ##STR56## R is hydrogen or a group of the formula --CO--CH═CH₂, G* is hydrogen or C₁ -C₁₂ alkyl, R₂₅ is C₁ -C₁₈ alkyl, phenyl or a group --(CH₂)_(c) --CO--OR₂₈ or --CH₂ CH₂ OR₃₃, R₂₆ is hydrogen, C₁ -C₁₈ alkyl, phenyl, benzyl or a group ##STR57## or --(CH₂)_(c) --CO--OR₂₈ or --CH₂ --CH₂ --OR₃₃, R₂₇ is C₁ -C₃₀ alkyl or one of the groups --CHR₃₁ --CH₂ --S--R₃₂, ##STR58## wherein Q is C₂ -C₈ alkylene, C₄ -C₆ thiaalkylene or a group --CH₂ CH₂ (OCH₂ CH₂)_(d) --, R₂₈ is C₁ -C₂₄ alkyl, R₂₉ is hydrogen, C₁ -C₁₈ alkyl or cyclohexyl, R₃₀ is C₁ -C₁₈ alkyl, cyclohexyl, phenyl, phenyl substituted by C₁ -C₁₈ alkyl, or one of the groups ##STR59## R₂₉ and R₃₀ together are C₄ -C₈ alkylene that may be interrupted by --O-- or --NH--, R₃₁ is hydrogen, C₁ -C₄ alkyl or phenyl, R₃₂ is C₁ -C₁₈ alkyl, R₃₃ is hydrogen, C₁ -C₂₄ alkyl, phenyl, C₂ -C₁₈ alkanoyl or benzoyl, R₃₄ is C₁ -C₁₈ alkyl, cyclohexyl, phenyl, phenyl substituted by C₁ -C₁₈ alkyl, or a group ##STR60## R₃₅ is hydrogen, C₁ -C₁₈ alkyl, cyclohexyl, or a group ##STR61## R₃₄ and R₃₅ together are C₄ -C₈ alkylene, which may be interrupted by --O-- or --NH--, R₃₆ and R₃₇ are --S--C₁ -C₁₈ alkyl, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, c is 1 or 2, d is from 1 to 5, f is from 2 to 8 and q is 1, 2, 3 or
 4. 6. A process according to claim 5 where in the stabilized composition,A is hydrogen, C₁ -C₈ alkyl, cyclohexyl, phenyl or a group --CH₂ --R₃₆ or ##STR62## D is C₁ -C₈ alkyl, cyclohexyl, phenyl or a group --CH₂ --R₃₇, X is hydrogen, C₁ -C₈ alkyl or one of the groups --C_(a) H_(2a) --S_(q) --R₂₆, --C_(b) H_(2b) --CO--OR₂₇, --CH₂ N(R₃₄)(R₃₅), ##STR63## R₂₆ is C₁ -C₁₂ alkyl, phenyl or a group --(CH₂)_(c) --CO--OR₂₈, R₂₇ is C₁ -C₁₈ alkyl or a group ##STR64## wherein Q is C₂ -C₈ alkylene, --CH₂ --CH₂ --S--CH₂ CH₂ or a group --CH₂ CH₂ (OCH₂ CH₂)_(d) --, R₂₈ is C₁ -C₁₈ alkyl, R₃₄ and R₃₅ are each, independently of the other, hydrogen or C₁ -C₁₂ alkyl or R₃₄ and R₃₅ together are C₄ -C₈ alkylene which may be interrupted by --O-- or --NH--, a is 1 or 2, b is 1 or 2, c is 1 or 2, and d is 1, 2 or
 3. 7. A process according to claim 6 where in the stabilized composition,A is hydrogen, C₁ -C₆ alkyl, --CH₂ --R₃₆ or a group ##STR65## D is hydrogen or C₁ -C₁₈ alkyl, and X is hydrogen, C₁ -C₄ alkyl, --CH₂ --R₃₆ or a group of the formula ##STR66##
 8. A process according to claim 1 where in the stabilized composition, in component D), R₃₈ and R₃₉ are each, independently of the other, phenyl or phenyl substituted by C₁ -C₁₂ alkyl, or together form a radical of the formula IV.
 9. A process according to claim 1 where in the stabilized composition, in component D),R₃₈ and R₃₉ form a radical of the formula IV wherein R₄₀ and R₄₁ are C₆ -C₁₂ alkyl and R₄₂ is hydrogen,or component D) is a commercial mixture obtained by reacting diphenylamine with diisobutylene, comprising a) diphenylamine; b) 4-tert-butyldiphenylamine; c) compounds from the groupi) 4-tert-octyldiphenylamine, ii) 4,4'-di-tert-butyldiphenylamine, iii) 2,4,4'-tris-tert-butyldiphenylamine, d) compounds from the groupi) 4-tert-butyl-4'-tert-octyldiphenylamine, ii) o,o'-, m,m'-, or p,p'-di-tert-octyldiphenylamine, iii) 2,4-di-tert-butyl-4'-tert-octyldiphenylamine, e) compounds from the groupi) 4,4'-di-tert-octyldiphenylamine, ii) 2,4,-di-tert-octyl-4'-tert-butyldiphenylamine, and wherein not more than 5% of component a), 8 to 15% b), 24 to 32% c), 23 to 34% d) and 21 to 34% e) are present.
 10. A process according to claim 1 where in the stabilized composition, in component B), R₂ is hydrogen.
 11. A process according to claim 1 where in the stabilized composition, in component B),R₁, when m=1 and G is a direct bond, is hydrogen, C₁ -C₁₈ alkyl, C₃ -C₁₈ alkenyl, C₂ C₁₈ alkanoyl, C₃ -C₁₈ alkenoyl, benzyl, phenyl or C₁ -C₄ alkyl-substituted phenyl, C₅ -C₈ cycloalkyl, C₃ -C₁₈ -alkyl, -alkanoyl or -alkenyl interrupted by oxygen, sulfur or by >NR₁₆, C₆ -C₉ cycloalkoxycarbonyl, benzoyl, or C₁ -C₈ alkyl-substituted benzoyl, or R₁, when m=2 and G is a direct bond, is --CO--R₁₇ --CO--, or R₁, when m=1 and G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ --C₁₈ alkoxy, C₃ -C₁₈ alkoxy interrupted by oxygen, sulfur or by >NR₁₃, benzyloxy, C₅ -C₈ cycloalkoxy, unsubstituted or C₁ -C₈ alkyl-substituted phenoxy, --NR₁₄ R₁₅ or ##STR67## or R₁, when m=2 and G is a group --CR₁₈ R₁₉ --CO--, is C₂ -C₁₂ alkanedioxy, or C₃ -C₂₅ alkanedioxy interrupted by oxygen, R₂ and R₄ are hydrogen, R₃ and R₅ are each, independently of the other, hydrogen, C₁ -C₁₈ alkyl, C₇ -C₉ phenylalkyl, benzyl, phenyl, C₅ -C₈ cycloalkyl, C₁ -C₈ alkoxy, hydroxy, C₁ -C₁₈ alkanoyloxy, C₃ -C₁₈ alkenoyloxy or benzoyloxy, or a radical of the formula --(CH₂)_(n) --CO--OR₆ or --(CH₂)_(n) --CO--N(R₇)₂, and R₃, when m=1, is in addition a radical of the formula --Y--E, R₁₇ is a direct bond, C₁ -C₁₂ alkylene, C₂ -C₁₂ alkylene interrupted by oxygen, sulfur or by >NR₁₆, C₂ -C₁₂ alkylene, C₂ -C₁₂ alkylidene, C₇ -C₁₂ phenylalkylidene, C₅ -C₈ cycloalkylene or phenylene.
 12. A process according to claim 11 whereinm=1 and, R₁, when G is a direct bond, is hydrogen, C₁ -C₁₈ alkyl, C₂ -C₁₈ alkanoyl, C₃ -C₄ alkenyl, C₃ -C₁₈ alkenoyl, benzyl, C₅ -C₈ cycloalkyl, or C₃ -C₁₈ alkyl or -alkanoyl interrupted by oxygen, or R₁, when G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₁₈ alkoxy, C₃ -C₁₈ alkoxy interrupted by oxygen, unsubstituted or C₁ -C₈ alkyl-substituted phenoxy, --NR₁₄ R₁₅ or ##STR68## R₂, R₄, R₂₁ and R₂₄ are each independently of the other, hydrogen or C₁ -C₄ alkyl, R₅ is hydrogen or C₁ -C₁₄ alkyl, and R₃ is hydrogen, C₁ -C₁₂ alkyl, C₁ -C₈ alkoxy, --(CH₂)_(n) --CO--OR₆, --(CH₂)_(n) --CO--N(R₇)₂, --(CH₂)_(n) --CO--OR₁₁ or --Y--E.
 13. A process according to claim 12 whereinR₁, when G is a direct bond, is hydrogen, C₁ -C₁₈ alkyl, benzyl, allyl, isoallyl, C₁ -C₁₈ alkanoyl, or C₁ -C₁₂ alkanoyl interrupted by oxygen, or R₁, when G is a group --CR₁₈ R₁₉ --CO--, is hydroxy, C₁ -C₁₈ alkoxy, unsubstituted or C₁ -C₄ alkyl-substituted phenoxy, --NR₁₄ R₁₅ or ##STR69## R₂ and R₄ are hydrogen, R₃ and R₅ are each, independently of the other, C₁ -C₁₈ alkyl interrupted by oxygen, or C₁ -C₄ alkoxy or cyclohexyl and R₃ in addition is a group --(CH₂)_(n) --CO--OR₁₁ wherein R₁₁ is hydrogen or C₁ -C₄ alkyl, and R₁₄ and R₁₅ are hydrogen or C₁ -C₄ alkyl.
 14. A polyurethane made by the process according to claim
 1. 